Videopac G7000

In fact it's a gaming console with some computer
capabilities. Introduced in late 1970s, it was one of the first "video
game" computers publicly available. In different countries there were
different names for it, so in USA it is known as Magnavox Odyssey 2,
while in Europe it's Philips Videopac G7000. The name Philips Odyssey or
Sierra G7000 is also known. In France, it was also released as Radiola
Jet 25.
This device has small set of I/O devices: Two joysticks (connected with
non-detachable cables) and alphanumeric, membrane keyboard, video output
is also quite poor. Software is started from ROM cartridges inserted
before powering on. Some cartridges (such as "Computer Intro") allow to
emulate simple programming language.

The computer runs with Intel 8048 microcontroller as
CPU, with specific software in chip's mask-ROM. Intel 8748 programmed
with the same code can be used directly. Picture is generated by Intel
8245 circuit. Memory is also scarce - CPU has 64 bytes, 8245 can use
128. This allows to run simple games and only few other programs.

Manufacturer

Philips

Origin

France

Year of unit

ca. 1984

Year of introduction

1978

End of production

1984

CPU

Intel 8048

Speed

1.79MHz

RAM

64 (CPU)+128 (A/V) BYTES of
RAM

ROM

1kB

Colors:

8 out of 16

Sound:

Mono, simple generator with noise.

OS:

None

Display modes:

160x200

Media:

Cartridge

Power supply:

Built-in power supply giving 5V DC

I/O:

Built-in keyboard
Built-in 2 joysticks
RF out

Possible upgrades:

None (maybe except composite video output)

Software accessibility:

TOSEC

My unit had CPU damaged (/WR line) and it was replaced
by Intel 8748 EPROM-based controller. To re-program it a device for
Willem programmer must be built, it is available at
http://www.mpu51.com/eprom/eprom.html as MCS-48 adapter.

To use this adapter it's needed to raise programmer's
voltage to ca. 6V (PCB3B - remove a voltage controlling jumper), and
using it in this voltage is not much reliable too. In lower voltages it
may throw only FFs or 00s while reading.

Composite video output:

Composite video, with quite brighter colors, can be
found in mainboard as well as audio signal. The exact location of pins
with A (Audio), V (video) and GND (ground) is shown in the picture:

To explain - Looking at solder side: Video is the pin of
potentiometer closer to shielding. The second potentiometer's pin with
thick track is ground,. Audio signal is hidden partially under
shielding, it's the most bottom pin in the mainboard, near a bigger
ground plane.

Starting:

After powering up without cartridge there should be
garbage on screen. With cartridge, a game should start. Original Philips
cartridges have usually SELECT GAME screen in which game can be selected
with number keys. To return to this screen from game, press RESET.

If it won't satrt, clean cartridge connector in
cartridge and computer, then try again.

BEWARE! Components numbering in different schematics is
different. When manufactured, different versions, revisions and
countries had different numbering, so don't make mistakes by using one
numbering for another board. Generally, the circuit is the same or only
slightly different, but in some schematics even pins used by TTL logic
chips are different.